跨断层隧洞拟静力缩尺试验相似材料研究

SIMILAR MATERIALS FOR QUASI-STATIC SCALED TESTS OF FAULT-CROSSING TUNNELS

  • 摘要: 相似材料设计是保证试验模型与原型力学性质匹配的关键环节之一。依托滇中引水工程的香炉山隧洞,基于相似理论和量纲分析法,推导跨断层隧洞拟静力缩尺试验物理量的相似关系,进而以重晶石粉、河砂为骨料,以石膏、石灰为胶结材料,研制混凝土及岩体的模型相似材料,并通过一系列试验研究各组分对模型材料物理力学参数的影响。试验结果表明:高强石膏含量、水胶比可显著改变相似材料的强度、弹性模量和密度;当砂胶比取0.8~1.2时材料的强度变化较小,当砂膏比取3~12时材料的强度显著降低;以高强石膏、低强石膏、重晶石粉、河砂制配的相似材料可较好地模拟C30混凝土的弹塑性性能及脆性破坏模式;以高强石膏、石灰、河砂制配的相似材料可较好地模拟IV级、V级围岩的张拉劈裂破坏及斜剪破坏模式。该相似材料的研制过程和配比可为类似模型试验及数值模拟提供重要的参考依据。

     

    Abstract: The design of similar materials is one of the key links to ensure the matching of the physic-mechanical properties between the prototype and the test specimens. Based on the prototype of the Xianglu mountain tunnel of the water diversion project in the central Yunnan province, China, the scaling relationship of the physical quantities in the quasi-static scaled test of a fault-crossing tunnel is derived in this study according to the similarity theory and dimensional analyses. The similar materials of concrete and rock mass used in the test are developed with barite powder and sand as the aggregates and with gypsum and lime as the cementing material. The effects of each component on the physic-mechanical properties of the similar materials are investigated through orthogonal tests. The test results indicate that the strength, elasticity modulus and density of the similar materials can be significantly changed by the overall content of the high-strength gypsum and water-gypsum ratio. Small variation of the strength of the similar material is found when the sand-gypsum ratio is between 0.8 and 1.2, but the strength significantly decreases when the sand-gypsum ratio is between 3 and 12. The elastoplastic performance and the brittle failure mode of Grade C30 concrete can be well simulated by the similar material made of high strength gypsum, low strength gypsum, barite powder and sand. The tensile splitting and the diagonal shear failure modes of rock mass of Grade IV and V can be well simulated by the proposed similar material made of high strength gypsum, lime and sand. The development process and ratios of similar materials can provide important reference for model test and numerical simulation.

     

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